Cyclometalated Platinum(II) Complexes with Mesoionic Dibenzofuranyl-1,2,3-triazol-4-ylidene Ligands: Synthesis, Characterization and Photophysical Properties

Platinum(II) complexes with mesoionic C perpendicular to C*-cyclometalating 1,2,3-triazolylidene ligands are highly efficient phosphorescent emitters. Herein we report a series of this type bearing dibenzofuranyl-substituted carbenes along with different beta-diketonate auxiliary ligands. They show luminescence in the green region of the visible spectrum and quantum yields of up to 78 % at room temperature. The proposed molecular structures were verified by NMR spectroscopy and X-ray diffraction experiments which prove the formation of the mesoionic carbene. Additionally, DFT calculations and cyclic voltammetry measurements were used to rationalize the observed photophysical properties of the reported complexes.